Lennon Bruce, who was 15 at the time, pummelled the teenager before delivering a devastating final blow when he tried to get back to his feet.
A witness feared he’d kick his victim to death in the vile attack that took place on a road in Dundee back in November 2018, a court heard.
Bruce, now 18, admitted severely injuring the teenager in the brutal assault on Spey Drive when he appeared at Perth Sheriff Court and faces being locked up.
Sheriff William Wood told Bruce he had done himself "no favours" by booting his 15-year-old victim in the face while he was "at his weakest and most vulnerable".
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